Not really sure.

4x Renew and a PW: Shield is definitely a decent boost.
Popping out of shadow form for additional heals, is an option too.

You could create an action target group, for healing.
And then a mapped key, to determine if a given toon is in the heal ATG or not.
You could even go with a few such keys, so you can move multiple toons into or out of the group.
And then just hit your heal key, and each toon in the group (0 to 4) does a heal.

Really not sure if that's enough heals or not.. VE x4.
But one toon could easily go Disc, and act as a dedicated healer.
If the VE was not enough.